The present disclosure relates to a gas circuit breaker.
Generally, a gas circuit breaker is disposed on a power transmission line to disconnect the power transmission line for inspecting the power transmission line and other devices or protecting the power transmission line and load devices by interrupting a current in an abnormal condition. Particularly, a gas circuit breaker can safely protect an extra-high voltage power system by interrupting a fault current caused by a ground fault or short circuit. In more detail, so as to interrupt a fault current in an abnormal state having severe conditions, a gas circuit breaker compresses highly insulative arc-extinguishing gas and injects the arc-extinguishing gas at a high pressure through a nozzle to extinguish arcs generating while a current is interrupted.
In the case of a hybrid arc-extinguishing circuit breaker, arc energy of a fault current is used as an energy source of an expansion chamber to interrupt the fault current. For this, in an early current-interrupting operation stage of the hybrid arc-extinguishing circuit breaker, it is necessary to move a large amount of gas from a compression chamber to the expansion chamber.
FIG. 1 is a sectional view illustrating an insertion state of a gas circuit breaker of the related art, and FIG. 2 is a sectional view illustrating an open state of the gas circuit breaker.
Referring to FIGS. 1 and 2, the gas circuit breaker of the related art includes an interruption part for interrupting a fault current, and the interruption part is composed of a fixed part and a movable part. When a current is interrupted, the fixed part may not move, and the movable part may move.
In detail, the fixed part includes a fixed arc contact 1 and a fixed main contact 3. The movable part includes a nozzle 2, a movable arc contact 4, a cylinder 5, an expansion chamber 6, a compression chamber 7, and a manipulation device connecting part 8.
In current interruption mode, the entirety of the movable part is moved using energy received from a manipulation device. At this time, the compression chamber 7 is compressed, and thus gas can be injected at a high pressure through the expansion chamber 6 and the nozzle 2 for interrupting a fault high current. Gas injected from the compression chamber 7 extinguishes an arc generating when the contacts are opened, that is, an arc generating between the fixed arc contact 1 and the movable arc contact 4.
As described above, if the related-art gas circuit breaker has an arc-extinguishing part divided into the compression chamber 7 and the expansion chamber 6 to use arc energy for interrupting a fault current, sufficient expansion energy is necessary for current interrupting. Therefore, when the gas circuit breaker is initially operated, a large amount of SF6 gas is supplied into the compression chamber 7 to maintain the inside of the compression chamber 7 at a high pressure. However, this increases an expansion length of the gas circuit breaker or the cross-sectional area of the compression chamber 7.